1. Field of the Invention
The invention relates to image scaling, more particularly to a method and apparatus for image scaling using adaptive edge enhancement.
2. Description of the Related Art
As technology improves, integration of computer and consumer electronics has become a primary consideration to provide better functionality to consumers. When displaying a computer video graphics adapter (VGA) signal on a television screen, video signals are scaled to match the aspect ratio of digital television terminals. Image scaling in digital television terminals can provide different viewing flexibility for viewers.
Presently, image scaling uses linear interpolation or digital differential analyzer (DDA) to scale images. However, for different scaling factors, traditional approaches require a large hardware cost to meet real time video applications. In addition, image scaling often blurs the edges of differently colored portions in an image since interpolation acts as a low-pass filter when scaling images. Thus, edge enhancement has to be performed to make the scaled images sharper and clearer.
Conventional edge enhancement techniques do not produce good image quality since they do not consider image contents for subsequent image scaling. Since visual sensitivity of the human eye depends on the brightness of the background, adaptive edge enhancement can avoid the defects of conventional methods and can provide viewers with better image quality.